1. Field of the Invention
The present invention relates in general to the recording/reproduction of optical information, and more particularly to an optical disk-shaped recording medium in which tracks constitute blocks in the unit of a predetermined number, each of the blocks being provided with a data region and a first mapping region, a second mapping region being further provided on one of the blocks having a center one of the tracks, each of the first mapping regions including mapping sectors and replacement sectors, the second mapping region including a mapping information recording region and a replacement sector region for the first mapping regions of the whole of the blocks, and an apparatus and a method for recording/reproducing optical information using the optical disk-shaped recording medium in which bad sectors of the entire tracks can efficiently be handled.
2. Description of the Prior Art
Generally, in recording media such as optical disks, the recording/reproduction of optical information is performed by applying a laser beam condensed in the order of 1 .mu.m to the optical disks. At this time, various errors may be generated due to dust or alien substances on the surfaces of the optical disks and defects thereon. In the optical disk having a so-called track/sector construction, data is encoded and reproduced in the unit of sector for error detection and correction. Conventionally, since error detection/correction codes are in the unit of sector of 512 KByte, they cannot be applied to a disk having a considerable interleave length such as, for example, a compact disk (CD) not employing the sector construction. Also, in the case where burst errors affecting the entire sectors are generated, they cannot be corrected, resulting in abnormal reproduction of the data, differently from random errors occurring at a part of the sectors.
As one of methods for solving the above problem, there is known a replacement method for the optical disk of the recording type in which bad sectors are detected by a reading discrimination operation of reproducing the recorded data, just after the recording to discriminate whether the recorded data is accurately reproduced, and information on the detected bad sectors are recorded on replacement sectors which are formed on particular regions of the optical disk. However, the above-mentioned replacement method has a disadvantage in that the management of the replacement sectors is complex and difficult since the defects on the optical disk of the recording type are increased due to the natural life of the disk and the number of recording times, resulting in an increase in the replacement time.
Also, the optical disk of the reproduction-only type cannot employ the reading discrimination operation since it is stamped in large quantities in a manufacturing plant. As a result, all of the manufactured disks must be read again to search for bad ones among the disks. Reading all the manufactured disks results in an increase in the manufacturing cost.
In a conventional apparatus for recording/reproducing optical information using such an optical disk, in the case where data is repeatedly recorded on the same sector of the optical disk, a bad sector detection circuit detects an error in a sector address to a sector identifier and recognizes a sector of the detected error as a bad sector. In this case, data recorded on a data region cannot be detected ahead of the sector address to the sector identifier. For this reason, data may be recorded on the bad sector. This degrades the reliability.
FIG. 1 is a diagrammatic view illustrating a recording format of a conventional optical disk-shaped recording medium which is shown in U.S. Pat. No. 4,925,717. As shown in this drawing, the conventional optical disk-shaped recording medium comprises tracks, each of which includes a predetermined number of sectors SC (for example, 32 sectors). Each of the sectors SC is partitioned into a predetermined number of blocks BL1-BLn (for example, 42 blocks), each of which is provided with a control recording region (referred to hereinafter as ARC) and an information writing region (referred to hereinafter as ARD). The ARC is provided with a servo region (referred to hereinafter as ARS) and a traverse region (referred to hereinafter as ART). The ARS is provided with a pair of tracking information pits (referred to hereinafter as QA and QC) and a clock information pit (referred to hereinafter as QB). The ART is provided with a pair of traverse information pits (referred to hereinafter as QD and QE) every 16 consecutive tracks. The use of the QD and QE makes the counting of traverses more accurate and, thus, the tracking more accurate.
In other words, the QD and QE are provided on the ART at n interval from each other of a distance P. The QD is shifted at an interval of 4 consecutive tracks, whereas the QE is shifted for each track. The traverse counting is performed in the unit of track by the QD and QE. Therefore, data regarding the number and direction of track jumps can be obtained based on the QD and QE and the tracking can thus be performed more accurately on the basis of the obtained data.
However, the above-mentioned U.S Patent is desirable to make the tracking more accurate by performing the traverse counting at an interval of one track, but has the disadvantage that it cannot propose how to skip a bad sector resulting from an error of the disk and record information on the bad sector on a different region.